The present invention relates to a toggle latch and, more particularly, to a toggle latch having an automatic safety catch which locks the latch in its toggle position.
Toggle latches have been used in various environments including aircraft for many years. A toggle latch similar to the latch in which the present invention is incorporated has been used in various locations on an aircraft fuselage including in front of engine inlets. Historically, doors closed by toggle latches have been difficult to rig properly to ensure that the doors remain closed. Should a door open in flight, it could be ingested by the aircraft engine, causing shutdown due to foreign object damage. To overcome this accidental opening, the toggle latches have been made adjustable by providing a screw adjustment within the latch member. This permits the toggle latch to place a preload upon the door and frame. However, since the load rigging is left to the mechanic, it is not certain that the adjustment will be correct. Underadjustment will create a gap between the door and frame allowing destructive vibration or airflow to tear the door from the aircraft. Overadjustment of the adjustable screw on the latch bolt can reduce the over-center movement of the toggle latch and even permit the latch to appear to be closed while in an on-center, and thus unlocked, position. This could also create an unsafe condition and result in the door, upon which the latch is used, opening while the aircraft is in flight.